How to add glitter effect in 3D render
It's very easy, 


Go to the compositor
Make sure you check use nodes
Add a glare node in between "render layers" and "composite"
Set it to "fog glow" and try various settings till you get desired effect(s)
"Threshold" controls pretty much how much glow there is
The lower it is the more glow
"Size" controls how blurry is the glow
I normally use only those two settings


Voila !!! Magic lights.